Union of rubber to metal



Oct. 25, 1932.

S. S. KURTZ, JR

UNION OF RUBBER T0 METAL Filed March 2. 1928 gnw'ntot dlemzz-Z 611K 21212.72:

, tively hard Patented Octi25, 1932 UNITED STATES. PATENT OFFICE STEWART S. KUBTZ, 33., AKRON, OHIO, ASSIGNGB TO THE GOODYEAR T133 RUBBER COMPANY, OF AKRON,

01110, a conrona'rron or 0310 UNION OI! RUBBER 'IO METAL Application filed. March 2, 1928. Serial 1T0. 258,885.

This invention relates to methods for unitingrubber and metal. It has for one of its objects the provision of a substance which adheres tenaciously both to metal and rubber to 5 effect a permanent bond therebetween. A further 0 ject of the invention is to provide a method that involves the vulcanization of the rubber in the presence of certain metallic salts, thereb to secure a strong and perma- 9 nent union etween the metal and the rubber. Other objects will be apparent as the description of the invention proceeds.

Two methods have heretofore commonly been used in order to unite rubber and metallic surfaces. One method consists in first plating the metallic surface with a thin layer of brass by the electro deposition of copper and zinc thereon. The rubber is then pressed firmly into contact with the brass coating and subjected to a relatively long cure at a comparatively high temperature.

Another. method for effecting the same pur-' pose consists in applying a coating or layer 06 of rubber containing a high percentage of sulphur to a metallic surface, for example, to

base bands or rims such as those employed as seats for, solid rubber tires. A layer of rubber, such as tread stock, is next superposed upon the first mentioned layer, which is relaand inextensible, and the whole is subjected to the action of a comparatively high pressure and temperature for a considerable period of time.

Both of these methods are objectionable, in

accurate control of all of the conditions existing during the process. If such control is not exercised, poor unions are obtained.

This invention involves the discovery that a union may readily be brought about between metal and rubber if a small amount of a copper or cobalt salt is spread upon the surface of either the rubber or the metal prior to the application of heat and pressure for purposes of vulcanization. For a better understanding pf the invention, reference may now be had to the accompanying drawing, forming a part of the specification, in Which,

Figure 1 is a perspective view showing a part because their use necessitates extremely sheet of rubber secured to a metallic plate in accordance with my invention; and

Figure 2 is a cross-sectional view of the embgdiment of the invention disclosed in Figure In racticing the invention, a metallic body, or example, a plate 5 of soft-steel containing approximately .096 percent of carbon, .04 percent of sulphur, .44 ercent of manganese and .02 percent of piiosphorus, .is coated thinly with a layer of cement 6 comprising a 5 percent solution of a copper or cobalt oleate in benzene. The cement is applied with a brush, spray or by any other convenient method. The layer of the oleate solution is permitted to dry for a period of approximately ten minutes and is then coated with a layer of rubber cement containing approximately 3.2 percent of solids. The latter coating is permitted to stand for a period of approximately one-half hour, after which the surface thereof is moistened with a convenient rubber solvent, such as benzene or gasoline.

A layer of rubber 7 consisting of raw rubber compounded with the desired quantities of sulphur, pigments, accelerators, etc., is then pressed upon the moistened surface of the cementing la er. The article thus formed is placed in a mo d and cured at a temperature corresponding to that of steam under forty pounds pressure for a period of approximately two and one-half hours and with the application of a positive pressure.

The'invention is not limited to the employment of the oleate salts of cop er and cobalt to obtain adhesion between rub er and metal. Similar results may be obtained by the use of the stearates, palmitates and other copper or cobalt salts of various unsaturated 00 acids of the olefin series and also acids of the pa-rafin series, such as the salts produced by the interaction of acetic acid and copper. Adhesion of rubber tometal may also be obtained by the employment of a .,rubber cement containing copper or cobalt salts of mercaptobenzothiazole as an adhesive. Effective adhesion may also be obtained by the employment ofinorganic salts, 'such as copper or cobalt chloride. This is 400 umes of benzene.

In order to obtain a union of rubber to metal by the employment of copper chloride, it is preferable to mix one volume of a two and one-half percent dispersion of cuprous chloride (Cu cl in alcohol with two vol- This solution is poured with vigorous agitation into two volumes of diluted rubber cement. .The compounds so prepared may be applied to metal surfaces, such as a mild steel, with a brush or by spraying. A rubber stock containing suitable quantities of sulphur and other ingredients desired is ressed upon the surface and then cured y the application of heat and pressure.

It is also'possible to obtain a union of rubber to metal by dusting the surfaces to be secured together with owdered copper or cobalt salts and then subjecting the rubber to cure in the same manner as in the examples previousl described. In this case, the rubber absor s the salt directly and a layer of compound ca able of adhering to the metal is thus pr need when the stock is subjected to heat and pressure during vulcanization.

Adhesion may likewise be obtained by intermixing a copper or cobalt salt, such as cu rous chloride (Cu-3012) or cupric chloride uCl with a binder such as a bakelite varnish and then coating one of the surfaces to be secured together therewith. The rubber stock is then pressed upon the metal and subjected to cure in the ordinary manner.

It will be apparent from the preceding description that the invention involves a relatively simple method whereby excellent adhesion of rubber to metal may be obtained.

Although only the preferred forms which the invention; may assume have been described, it will be a parent to those skilled in the art that the invention is not limited thereto but that various modifications may be made therein without departing from the spirit thereof or from the scope of the appended claims. it is intended that the patent shall cover, by suitable expression in the appended claims, whatever features of patentable novelty reside in the invention.-

What I claim is:

1. A method of securing rubber surfaces to metallic surfaces which comprises coating one of the surfaces with material coning an organic salt of copper or cobalt, bringing the surfaces together and applying heat andfpressure thereto.

9. A method of securing a union of rubber to metal which comprises coating one of the surfaces to be secured with a mate rail containing a copper or cobalt salt of an unsaturated organicacid, intimately gaging the surname with each other, and

subjecting the rubber to heat and pressure.

3. A method of treating rubber which comprises causing its surfaces to adhere to an iron-containing body by the action of a cop eror cobalt salt whilethe surfaces are hel in contact by pressure and are subjected to heat. j

4.. A method of treating rubber which comprises causinga surface thereof to adhere to an iron-containing body by the action of an organic salt of copper or cobalt while the surfaces are held in contact by pressure and while they are subjected to heat. 7

5. A method of treating rubber which comprises causing a surface thereof to adhere to an iron-containing body by the action of a copper or cobalt salt of an unsaturated fatty acid while the surfaces are held in contact by pressure and while they are subjected to heat.

6. A method of treating rubber which comprises causing a surface thereof to ad here to an iron-containing body by the action of a copper or cobalt oleate while the surfaces are held in contact by pressure and while they'are subjected to heat.

7. An article comprising a body of ironcontaining material and a body of rubbercontaining material united to the first mentioned body by means of an intermediate layer of material containing a salt of copper or cobalt.

8. An article comprising a body of ironsaturated hydrocarbon acid and copper or cobalt.

10. An article comprising a body of iron containing material and a body of rubbercontaining material united to the first mentioned body by means of an intermediate layer of material containing an oleate salt of cop er or cobalt.

11. i method of forming a composite body consisting of a ply of ru ber and a ply of steel comprising disposing a film of an organic salt of copper between the two plies and then subjecting the whole to heat and pressure. v

12. A method of securing rubber to metal which comprises uniting the same by means of a cement containing copper oleate and subjecting the rubber to vulcanization under heat and pressure.

13. A method of securing rubber to metal which comprises cementing those materials together by means of a cement containing a oleates paimitetes and stearate's of: copper and eobait, and subjecting the rubber to vul= cenization under heat and pressure.

14:. A method or securing rubber to ferrous metal comprising the steps of dispsre ing a salt of copper or cobalt in a, ru bier cement, interposmg a layer of the cement between the rubber and the ferrous metal and uniting the whole by the application 0% bent and pressure.

15. Amethod of securing rubber to ferrous metal comprising the steps of applying to at least one of the surfaces to be secured together a rubber cement containing a salt of copper or cobalt in which the valence of the copper or cobalt is two and thereafter subjecting the whole to the action of heat and pressure.

16. A method of securing rubberto fer rous metal comprising interposing between the rubber and the metal e body of rubber cement having an organic copper orcobelt salt dispersed therein.

17. A method of securing rubber to ferrous metal comprising the steps of coating seid ferrous metal with 9. salt oi copper or cobalt dispersed in a liquid vehicle, applying a body of rubber cement over said costing, superimposing on said body of rubber cement the rubber to be secured to said ferrous metal and vulcenizing the rubber.

18. A method of securing rubber to fer rous metal comprising the steps of meeting said ferrous metal with a salt of copper or cobalt, applying a rubber cement over said coating, superimposing the rubber to be secured to sald ferrous metal and vulcanizing.

In witness whereof, I have hereunto signed my name.

Si ed at Akron, in the county of. Summit and tute of Ohio, U. S. A., this 29th day of February, 1928.

STEWART S. KURTZ, JR.- 

